1. Field of the Invention
The present invention relates to security protection in an access to a network device.
2. Description of the Background Art
In a conventional network, a client typically accesses to a device connected to the network (referred to as network device) by using a unique Internet Protocol address (hereinafter referred to as IP address) of the device. Also, the client acquires the IP address corresponding to a domain name of a network device from a name server on the network, so that the client can access to the IP address to specify the network device.
In the access to the network device, an access may be performed for not only a legal object but also an illegal object, a security measurement must be employed against an illegal act. As the device security method, for example, the following methods are performed.
(a) In a device which is directly accessed through a network, a combination of user names and passwords managed by the device is checked, or only passwords is checked to protect the security.
(b) The combination of user names and passwords is checked on a server to protect the security when the server exists in the middle of access through the network.
In a conventional security protection, the combination of user names and passwords is mainly checked to manage the security protection. The IP address for specifying the network device is not sufficiently protected for security. More specifically, since a unique IP address allocated to the network device is disclosed on the network, the network device can be accessed by using the IP address. Since the IP address unique to the network device is necessary to specify the network device, the IP address is generally static, and security protection of the IP address is not considered against IP attack.